Optical signal emitting direction control apparatus and optical signal emitting direction control method

Abstract

An optical signal emitting direction control method of a present embodiment includes arranging a transparent member to extend over an underwater space and an in-air space, causing an optical signal to enter the transparent member from the underwater space via a surface of an underwater portion of the transparent member immersed in the underwater space, and causing the optical signal entered the transparent member to be emitted into the in-air space via a surface of an in-air portion of the transparent member exposed to the in-air space.

The invention claimed is: 
     
         1 . An optical signal emitting direction control apparatus, comprising a transparent member arranged to extend over an underwater space and an in-air space, wherein
 an inclination angle of a surface of an in-air portion of the transparent member exposed to the in-air space is changeable,   an optical signal to be transmitted from the underwater space to the in-air space enters the transparent member from the underwater space via a surface of an underwater portion of the transparent member immersed in the underwater space, and thereafter, is emitted into the in-air space via the surface of the in-air portion,   the transparent member includes a plurality of small members in a height direction, and   a number of the small members stacked in the height direction is changeable according to a fluctuation of a water surface, and a height of the transparent member is adjusted by the number of the small members.   
     
     
         2 . The optical signal emitting direction control apparatus according to  claim 1 , wherein
 at least one of a refractive index and a polarization characteristic of the transparent member is changed by application of a voltage.   
     
     
         3 . The optical signal emitting direction control apparatus according to  claim 1 , wherein
 an emitting direction of the optical signal emitted from the surface of the in-air portion into the in-air space is controlled by adjusting at least one of an incident angle of the optical signal incident on the surface of the underwater portion from the underwater space and an inclination angle of the surface of a portion of the in-air portion irradiated with the optical signal.   
     
     
         4 . The optical signal emitting direction control apparatus according to  claim 1 , wherein
 the transparent member includes a plurality of small regions having refractive indices different from each other, and   an emitting direction of the optical signal emitted from the surface of the in-air portion into the in-air space is controlled by changing at least one of a refractive index of each of the plurality of small regions and a relative arrangement of the plurality of small regions.   
     
     
         5 . The optical signal emitting direction control apparatus according to  claim 1 , wherein
 a color of at least a portion of the transparent member is a same color as an environmental color around the transparent member.   
     
     
         6 . An optical signal emitting direction control apparatus, comprising
 a transparent member arranged to extend over an underwater space and an in-air space,   wherein   an inclination angle of a surface of an in-air portion of the transparent member exposed to the in-air space is changeable,   an optical signal to be transmitted from the underwater space to the in-air space enters the transparent member from the underwater space via a surface of an underwater portion of the transparent member immersed in the underwater space, and thereafter, is emitted into the in-air space via the surface of the in-air portion,   at least one of a refractive index and a polarization characteristic of the transparent member is changed by application of a voltage.   
     
     
         7 . The optical signal emitting direction control apparatus according to  claim 6 , wherein
 an emitting direction of the optical signal emitted from the surface of the in-air portion into the in-air space is controlled by adjusting at least one of an incident angle of the optical signal incident on the surface of the underwater portion from the underwater space and an inclination angle of the surface of a portion of the in-air portion irradiated with the optical signal.   
     
     
         8 . The optical signal emitting direction control apparatus according to  claim 6 , wherein
 the transparent member includes a plurality of small regions having refractive indices different from each other, and   an emitting direction of the optical signal emitted from the surface of the in-air portion into the in-air space is controlled by changing at least one of a refractive index of each of the plurality of small regions and a relative arrangement of the plurality of small regions.   
     
     
         9 . The optical signal emitting direction control apparatus according to  claim 6 , wherein
 a color of at least a portion of the transparent member is a same color as an environmental color around the transparent member.   
     
     
         10 . An optical signal emitting direction control apparatus, comprising
 a transparent member arranged to extend over an underwater space and an in-air space,   wherein   an inclination angle of a surface of an in-air portion of the transparent member exposed to the in-air space is changeable,   an optical signal to be transmitted from the underwater space to the in-air space enters the transparent member from the underwater space via a surface of an underwater portion of the transparent member immersed in the underwater space, and thereafter, is emitted into the in-air space via the surface of the in-air portion,   the transparent member includes a plurality of small regions having refractive indices different from each other, and   an emitting direction of the optical signal emitted from the surface of the in-air portion into the in-air space is controlled by changing at least one of a refractive index of each of the plurality of small regions and a relative arrangement of the plurality of small regions.   
     
     
         11 . The optical signal emitting direction control apparatus according to  claim 10 , wherein
 a color of at least a portion of the transparent member is a same color as an environmental color around the transparent member.   
     
     
         12 . The optical signal emitting direction control apparatus according to  claim 10 , wherein an emitting direction of the optical signal emitted from the surface of the in-air portion into the in-air space is controlled by adjusting at least one of an incident angle of the optical signal incident on the surface of the underwater portion from the underwater space and an inclination angle of the surface of a portion of the in-air portion irradiated with the optical signal.